Born in Glasgow in 1860, Kay studied at the Glasgow School of Art under Robert Greenlees, then later at the Academie Julien in Paris under Boulanger. On his return home he spent 18 years teaching at various schools in the city before settling in Callander, Perthshire.
Despite being city-based Kay was almost exclusively a landscape painter, working frequently in the Western Highlands, Arran and Iona, but also in France, Belgium, Italy, Denmark and Holland.
He was president of the Glasgow Art Club and a long time member of the Royal Scottish Watercolour Society, the Royal Scottish Academy and the Royal British Colonial Society of Artists.